The catalyst-free reactions of Baylis-Hillman alcohols (1a-i) with 2-aminobenzimidazole (2) in THF-H2O (1:4) were developed for the convenient and greener synthesis of benzimidazo[1,2-a]pyrimidinone derivatives (3a-i)...The catalyst-free reactions of Baylis-Hillman alcohols (1a-i) with 2-aminobenzimidazole (2) in THF-H2O (1:4) were developed for the convenient and greener synthesis of benzimidazo[1,2-a]pyrimidinone derivatives (3a-i).The pesticidal activities of 3a-i were examined to investigate a new biological activity of the imidazo[1,2-a]pyrimidinone-type compounds.展开更多
Herein,we report tunable asymmetric addition and telomerization of butadiene by synergistic chiral primary amine/achiral palladium catalysis.A selection of different achiral phosphine ligand in concert with the chiral...Herein,we report tunable asymmetric addition and telomerization of butadiene by synergistic chiral primary amine/achiral palladium catalysis.A selection of different achiral phosphine ligand in concert with the chiral primary amine-trifluoromethanesulfonic acid(TfOH)conjugates enables both chemo-and enantioselective control of the coupling with butadiene.Bidentate[(oxydi-2,1-phenylene)-bis-(diphenylphosphine)](DPEPhos)ligand led to 1,4-addition adduct whereas monodentate(p-Tol)3P ligand gave the telomerization product.A range ofα-branchedβ-ketoesters and aldehydes could be applied to afford allylation or telomerization products bearing allcarbon quaternary centers at high efficiency and good chemo-,regio-,and stereoselectivities.展开更多
A number of azacalix[2]pyrimidine[2]triazines were synthesized in moderate to good yields from both a step-wise fragment coupling approach and a one-pot reaction strategy starting from 4,6-diaminopyrimidines and cyanu...A number of azacalix[2]pyrimidine[2]triazines were synthesized in moderate to good yields from both a step-wise fragment coupling approach and a one-pot reaction strategy starting from 4,6-diaminopyrimidines and cyanuric chloride.Nucleophilic aromatic substitution reaction of resulting dichloro-substituted azacalix[2]-pyrimidine[2]triazines with NH_(4)Cl led to the formation of NH_(2)-bearing azacalix[2]pyrimidine[2]triazine analogs.Azacalix[2]pyrimidine[2]triazines adopted symmetric 1,3-alternate conformations in solution while twisted 1,3-alternate conformations were observed in the solid state.In the presence of different additives during the growth of single crystals,azacalix[2]pyrimidine[2]triazines containing amino(-NH_(2))groups gave varied self-assembled structures due to the formation of different intermolecular hydrogen bond motifs.展开更多
基金supported by the National Natural Science Foundation of China, Ministry of Science and Technology (2009ZX09501-006) and the Chinese Academy of Sciences
文摘The catalyst-free reactions of Baylis-Hillman alcohols (1a-i) with 2-aminobenzimidazole (2) in THF-H2O (1:4) were developed for the convenient and greener synthesis of benzimidazo[1,2-a]pyrimidinone derivatives (3a-i).The pesticidal activities of 3a-i were examined to investigate a new biological activity of the imidazo[1,2-a]pyrimidinone-type compounds.
基金the Natural Science Foundation of China(nos.21672217,21861132003,and 22031006)Tsinghua University Initiative Scientific Research Program for financial support.
文摘Herein,we report tunable asymmetric addition and telomerization of butadiene by synergistic chiral primary amine/achiral palladium catalysis.A selection of different achiral phosphine ligand in concert with the chiral primary amine-trifluoromethanesulfonic acid(TfOH)conjugates enables both chemo-and enantioselective control of the coupling with butadiene.Bidentate[(oxydi-2,1-phenylene)-bis-(diphenylphosphine)](DPEPhos)ligand led to 1,4-addition adduct whereas monodentate(p-Tol)3P ligand gave the telomerization product.A range ofα-branchedβ-ketoesters and aldehydes could be applied to afford allylation or telomerization products bearing allcarbon quaternary centers at high efficiency and good chemo-,regio-,and stereoselectivities.
基金We thank the National Natural Science Foundation of China(Nos.21132005,21121004)the Ministry of Science and Technology of China(Nos.2011CB932501,2013CB834504)for financial support.
文摘A number of azacalix[2]pyrimidine[2]triazines were synthesized in moderate to good yields from both a step-wise fragment coupling approach and a one-pot reaction strategy starting from 4,6-diaminopyrimidines and cyanuric chloride.Nucleophilic aromatic substitution reaction of resulting dichloro-substituted azacalix[2]-pyrimidine[2]triazines with NH_(4)Cl led to the formation of NH_(2)-bearing azacalix[2]pyrimidine[2]triazine analogs.Azacalix[2]pyrimidine[2]triazines adopted symmetric 1,3-alternate conformations in solution while twisted 1,3-alternate conformations were observed in the solid state.In the presence of different additives during the growth of single crystals,azacalix[2]pyrimidine[2]triazines containing amino(-NH_(2))groups gave varied self-assembled structures due to the formation of different intermolecular hydrogen bond motifs.
